Abstract The goal of this project is to transform clinical mapping by employing light emitting diodes to provide neurosurgsons with immediate visual feedback of the underlying cortical activity while enabling 100X higher spatial resolution for accurate resection of diseased tissue and preserving eloquent functional cortical regions. Intracranial functional mapping technology has only incremently evolved over the past several decades due to technological limitations. Here, we propose to utilize the integration of innovative display technologies on flexible biocompatible and transparent substrates to enable a technological leap in clinical diagnosis and understanding the ultimate limits of functional boundaries in the human brain. The bases for the proposed technology include (i) organic light emitting diodes (OLEDs) that are building blocks for high definition displays to be integrated on clinical and high-definition electrocorticography (ECoG) grids, (ii) oxide thin film transistors (TFTs) that are the backbone of screen displays, to increase the channel counts in ECoG, and (iii) novel electrode contact material with low electrochemical impedance at microscale, that is integratable with OLEDs and ECoG on flexible substrates. We envision a staged development of the technology that is divided into three advances. In Advance 1, we will integrate multi-color OLEDs on the back of clinical grids that will project different colors which correspond to cortical function during direct current stimulation (DCS) and/or somatosensory evoked potentials (SSEP) phase-reversal mapping of the central sulcus during tumor resection, and to the levels of interictal discharges in epilepsy resection. With this immediate visual feedback to the operating neurosurgeon and the transparency of the electrodes to the anatomical brain features, direct resection can commence potentially eliminating the need for manual placement of sterile paper markers on the cortical surface. In Advance 2, we will expand the accuracy and the determination of the resection boundaries beyond the 5mm for motor and 10mm for language by utilizing a high channel count grid electrode enabled by newly developed TFTs on thin, flexible and transparent substrates to maximize resection of diseased tissue and preservation of eloquent one. In Advance 3, we will investigate new levels of functional mapping of cortical organization by placing high density electrodes on the motor cortex and simultaneously use force and shear sensory feedback placed on the patient?s fingers. We will record and resolve cortical columns and the coordination of sensory and motor regions to produce function which will also be correlated to finescale movements and sensations of the fingers mapped by the pressure sensors. These technologies are anticipated to transform the streamlining of communicated information between neurosurgeons, neurolgists, and neurophysiologists via advanced monitoring and display technologies and would also lead to a shorter procedure and could reduce the risk of these procedures to the patients and their cost. Initial prototypes of the devices will be tested in adult pigs and then in the acute setting in the operating room under an institutional review board authorization.